The/a reader (again, question about articles)

Hi,

This is another question regarding usage of articles.


1. He published a book. He thought the/(none) readers would enjoy his story.
2. He wrote a English sentense. He expected the/(none) readers would understand it.
3. This website designer assumes that a/the visitor will press this button.
4. This website designer assumes that a/the visitor is a non English speaker.
5. This instrument is good for a handicapped player. (I'm sure this uses 'a')
6. This instrument is designed for a/the player who is handycapped.
7. This instrument assumes a/the player is handicapped.
8. In this hospital, every compartment has an emergency button along side the bed for the/(none) paitiants. A/The patient can use the button anytime to call the/a doctor.



I guess the both are accecptable for #1-4. For #6 and #7, I really don't know. #8 is a bit different kind, but also I don't know which I shold choose.